<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        * {
            padding: 0;
            margin: 0;
        }
        
        ul {
            width: 500px;
            margin: 50px auto;
        }
        
        li {
            width: 90px;
            height: 60px;
            list-style: none;
            border: 2px solid blue;
            overflow: hidden;
        }
        
        a {
            width: 90px;
            height: 60px;
            display: block;
            border: 2px solid red;
            position: relative;
            transform-style: preserve-3d;
            /* transform: rotateX(-20deg) rotateY(20deg); */
            transition: all .3s;
            transform-origin: bottom;
        }
        
        .front {
            width: 90px;
            height: 60px;
            background: url(img/small_front.png);
        }
        
        .back {
            width: 90px;
            height: 60px;
            background: url(img/small_back.png);
            color: #fff;
            text-align: center;
            line-height: 60px;
            /* font-size: 30px; */
            position: absolute;
            top: -60px;
            transform: rotateX(90deg);
            transform-origin: bottom;
        }
        
        a:hover {
            transform: rotateX(-90deg);
        }
    </style>
</head>

<body>
    <ul>
        <li>
            <a href="">
                <div class="front"></div>
                <div class="back">HTML</div>
            </a>
        </li>
    </ul>
</body>

</html>